In a marketing strategy for products and services, the acquaintance relation between persons sometimes referred to as personal connection or human network may become important. For example, when it is desired that a product or a service is purchased by a person, it is effective to have another person, who is trusted by that person, recommend to purchase the product or the service. However, acquaintance relation is not simple, and it is difficult to know a possibility that the most effective result is obtained when who gets an introduction from whom.
Conventionally, there has been proposed a technique graphically displaying relevance between persons, as a reference technique. However, according to this technique, providing the relevance between persons is effected by whether a plurality of names of persons are described in the same electronic document (text, for example) or not. Also, a node indicating a person is connected to a node indicating a person who is related to the former person by an edge. A graph created by repeating these connections is displayed for user.